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Aon plc is a leading global professional services firm focused on risk management, insurance and reinsurance brokerage, human capital consulting, and specialty insurance underwriting. It maintains dual headquarters in London, UK, and Chicago, US, operates across 120+ countries, and employed roughly 60,000 staff as of late 2024. Its name comes from the Gaelic word for "one", representing its goal of delivering unified client solutions.
Key moments
1982Founded via merger of Ryan Insurance Group and Combined International Corporation
2008Acquires Hewitt Associates and launches Aon Hewitt for human capital services
2021Announces merger plan with Willis Towers Watson, which is later blocked by EU regulators
2024Operates with approximately 60,000 employees across more than 120 global markets
Aon operates within the highly consolidated global insurance brokerage and risk management industry. The firm competes against a small set of large global peers and specialized regional competitors.
Its most significant rivals are:
Willis Towers Watson: The firm's closest competitor, with a nearly identical global service footprint; the two companies announced a planned merger in 2021 that was ultimately blocked by European Union antitrust authorities.
Arthur J. Gallagher & Co.: A US-based leader in commercial and specialty insurance, with a strong presence in North America.
HUB International: A mid-market focused competitor with a broad network of regional offices across North America and Europe.
Aon's key competitive strengths include its extensive international reach, diversified service portfolio, and deep industry expertise. It faces ongoing pressure from smaller, more agile competitors that offer lower-cost services, as well as regulatory scrutiny surrounding potential industry consolidations.
Ranks among the top three global providers of commercial insurance brokerage services
Primary competitors include Willis Towers Watson, Arthur J. Gallagher & Co., and HUB International
Leverages dual headquarters to balance European and North American client bases
Invests in data-powered technology to enhance its risk management and consulting offerings
As a leading global professional services brand operating across risk management, insurance and reinsurance brokerage, human capital consulting, and specialty underwriting, Aon has built robust, sector-leading brand equity anchored to its core founding promise derived from the Gaelic word for "one". This unified value proposition prioritizes seamless, end-to-end client solutions rather than siloed service delivery, distinguishing it from more fragmented peer firms in a highly consolidated industry.
Dual-headquartered in London, UK and Chicago, US, with a physical presence in over 120 countries and approximately 60,000 skilled employees as of 2024, Aon’s brand reputation is built on decades of delivering trusted, high-stakes advisory support to entities ranging from Fortune Global 500 corporations to public sector bodies and small and medium-sized enterprises. Its consistent track record of navigating complex cross-border risk, regulatory changes, and global crises has cemented its status as a go-to strategic partner for organizations seeking to mitigate volatile modern risks including climate change, cyber threats, and workforce disruption.
Aon further amplifies its brand influence through industry-leading thought leadership publications, global risk benchmarking reports, and cross-sector collaborative initiatives that shape public discourse around risk management best practices. Its strong brand identity reduces client acquisition friction, drives higher retention rates for high-value enterprise accounts, and supports its ongoing expansion into fast-growing emerging markets where demand for sophisticated risk advisory services is rising rapidly.
Brand leadership
Score: 92/100
Aon consistently ranks among the top 3 global players in the international insurance brokerage and risk management professional services segment, holding authoritative industry standard-setting status for complex cross-border risk structuring and specialty underwriting services. It outperforms the vast majority of mid-tier regional peers in penetration of high-value global enterprise accounts, and is regularly cited as a benchmark for service quality across its core service lines.
Stakeholder interaction
Score: 87/100
The firm maintains deep, long-standing two-way engagement with more than 50,000 active corporate clients across all major regions, delivering tailored advisory touchpoints aligned to each client’s unique risk lifecycle. Its widely distributed public industry reports and regular outreach to regulatory bodies, industry associations, and workforce advocacy groups foster high levels of trusted, reciprocal interaction across all its stakeholder segments.
Brand momentum
Score: 83/100
Following the 2021 termination of its planned high-profile merger with Willis Towers Watson, blocked by European Union antitrust regulators, Aon has delivered steady, above-industry-average organic revenue growth while pursuing targeted, low-risk strategic acquisitions across high-growth emerging markets, and expanding its fast-growing climate risk and cyber risk advisory service lines to capture new market share.
Brand stability
Score: 90/100
As a publicly listed firm with no major brand-eroding operational scandals or large-scale regulatory penalties recorded in its core operating markets over multiple decades, Aon has maintained consistent top-line performance through global economic downturns, major public health crises, and periods of widespread industry consolidation. It retains over 85% of its highest-value global enterprise client base on an annual basis.
Brand heritage
Score: 81/100
While the formal Aon brand identity was officially established in 1987, its core institutional operations trace back to mid-20th century foundational insurance and risk advisory businesses, giving it nearly 40 years of continuous, consistent brand presence in the global professional services market, supported by accumulated decades of deep institutional expertise across its service lines.
Industry profile recognition
Score: 89/100
Within the global insurance brokerage, risk management and human capital consulting sectors, the Aon brand name is universally recognized among industry practitioners and senior enterprise decision-makers. It holds a reputation for specialized complex risk advisory that few competing peer firms can match, making it the first choice for clients facing uniquely high-stakes, non-standard risk challenges.
Global brand reach
Score: 94/100
With operating locations spanning more than 120 countries and local specialist teams on every inhabited continent, Aon maintains one of the most geographically distributed footprints of any risk management services provider globally. Its localized service delivery model ensures consistent adherence to its unified "one client solution" brand promise, whether serving clients in mature developed markets or fast-expanding emerging economies.
AI-powered brand value reasoning frameworks can provide directional, illustrative analysis of Aon’s brand equity, market positioning, and incremental revenue-generating potential derived from its unmatched global footprint and decades of accumulated stakeholder trust. All estimates and analysis referenced in this encyclopedia supplement are for illustrative and educational analytical purposes only, and do not represent formally audited, independently verified brand value metrics. Parties seeking official audited brand valuation data for Aon are advised to contact the World Brand Lab directly to access its latest published authoritative assessment.
Financial services
services
Risk consulting
Retirement consulting
Health consulting
revenue
US$15.70 billion (2024)
operating income
US$3.835 billion (2024)
net income
US$2.654 billion (2024)
assets
US$48.96 billion (2024)
equity
US$6.121 billion (2024)
num employees
c. 66,000 (2024)
footnotes
‡R2R‡
Aon plc is a British-American[3]professional services firm.The company operates two divisions: Risk Capital (67% of 2024 revenues), which provides brokerage and consulting services for risk management and insurance and reinsurance, and Human Capital (33% of 2024 revenues), which provides services for health insurance, retirement plans, pension plans, and talent advisory.[2]
It is the second largest insurance broker worldwide.[4][5]
Founded in Chicago by Patrick Ryan, Aon was created in 1982 when the Ryan Insurance Group merged with the Combined Insurance Company of America under W. Clement Stone.In 1987, the holding company was renamed Aon from aon, a Gaelic word meaning "one".The company is globally headquartered in London with its North America operations based in Chicago at the Aon Center.
History
W. Clement Stone's mother bought a small Detroit insurance agency, and in 1918 brought her son into the business. Mr. Stone sold low-cost, low-benefit accident insurance, underwriting and issuing policies on-site. The next year he founded his own agency, the Combined Registry Co.[8]
As the Great Depression began, Stone reduced his workforce and improved training.Forced by his son's respiratory illness to winter in the South, Stone moved to Arkansas and Texas. In 1939 he bought American Casualty Insurance Co. of Dallas, Texas. It was consolidated with other purchases as the Combined Insurance Co. of America in 1947. The company continued through the 1950s and 1960s, continuing to sell health and accident policies. In the 1970s, Combined expanded overseas despite being hit hard by the recession.[8]
In 1982, after 10 years of stagnation under Clement Stone Jr., the elder Stone, then 79, resumed control until the completion of a merger with Ryan Insurance Co. allowed him to transfer control to Patrick Ryan.Ryan, the son of a Ford dealer in Wisconsin and a graduate of Northwestern University, had started his company as an auto credit insurer in 1964.In 1976, the company bought the insurance brokerage units of the
Legal issues
UK regulatory breach
In January 2009, Aon was fined £5.69 million in the UK by the Financial Services Authority, who stated that the fine related to the company's inadequate bribery and corruption controls, claiming that between 14 January 2005 and 30 September 2007 Aon had failed to properly assess the risks involved in its dealings with overseas firms and individuals. The Authority did not find that any money had actually made its way to illegal organisations. Aon qualified for a 30% discount on the fine as a result of its cooperation with the investigation. Aon said its conduct was not deliberate, adding it had since "significantly strengthened and enhanced its controls around the usage of third parties".[32]
US Foreign Corrupt Practices Act violations
In December 2011, Aon Corporation paid a $16.26 million penalty to the U.S. Securities and Exchange Commission and the U.S. Department of Justice for violations of the US Foreign Corrupt Practices Act.[33]According to the Securities and Exchange Commission, Aon's subsidiaries made improper payments of over $3.6 million to government officials and third-party facilitators in
Major acquisitions
In January 2007, Aon announced that its Aon Affinity group had acquired the WedSafe Wedding Insurance program.[35]
In August 2008, Aon announced that it had acquired London-based Benfield Group.The acquiring price was US$1.75 billion or £935 million, with US$170 million of debt.[36]
In March 2010, Hewitt Associates announced that it acquired Senior Educators Ltd. The acquisition offers companies a new way to address retiree medical insurance commitments.[37]
In July 2010, Aon announced that it had agreed to buy Lincolnshire, Illinois-based Hewitt Associates for $4.9 billion in cash and stock.[38]
In April 2011, Aon announced that it had acquired Johannesburg, South Africa-based Glenrand MIB.
Sponsorship of Manchester United
In June 2009, Aon signed a four-year shirt sponsorship deal with Manchester United F.C..On 1 June 2010, Aon replaced American International Group as the principal sponsor of the club.The Aon logo was prominently displayed on the front of the club's shirts until the 2014/2015 season when Aon was replaced by Chevrolet.[49] The deal was said to be worth £80 million over four years, replacing United's deal with AIG as the most lucrative shirt deal in history at the time.[49]
From 2013 to 2021 Aon owned the naming rights to the Trafford Training Centre and sponsored the club's training kits, reportedly worth £180 million to the club.[50]
Awards
Aon was awarded Investment Consultancy of the Year and Fiduciary Manager of the Year at the FT's 2014 Pension and Investment Provider Awards[51]
Aon received a perfect score on the Human Rights Campaign's 2013 Corporate Equality Index[52]
Aon was named to Working Mother's list of the 100 Best Companies for 2012[53]
Aon Risk Solutions was the most recommended broker in 2012 for service and expertise by middle market buyers in Business Insurance's Buyers Choice Awards[54]
Aon Risk Solutions was named Broker of the Year and Training Programme of the Year in 2012 by Insurance Times[55]
Ryan focused on insurance brokering and added more upscale insurance products.
He also trimmed staff and took other cost-cutting measures, and in 1987 he changed Combined's name to Aon.
In 1992, he bought Dutch insurance broker Hudig-Langeveldt.
In 1995, the company sold its remaining direct life insurance holdings to General Electric to focus on consulting.[9]
In June 1995, Aon acquired the Garden City based travel insurance firm Berkely Arm, Inc (also known as BerkelyCare Ltd. and The Berkely Group), known for providing travel insurance offerings to cruise lines and tour operators in the United States.This division eventually became known as Aon Affinity Travel Practice.[10]
Aon built a global presence through purchases. In 1997, it bought The Minet Group, as well as the insurance brokerage A&A Services, Inc., founded by Alexander Howden in the late 19th century.[11] It was then that insurance broker David Howden reclaimed the family brand name for the Howden Group.[12] These transactions made Aon (temporarily) the largest insurance broker worldwide.The firm made no US buys in 1998, but doubled its employee base with purchases including Spain's largest retail insurance broker, Gil y Carvajal, and the formation of Aon Korea.[13]
Responding to industry demands, Aon announced its new fee disclosure policy in 1999, and the company reorganised to focus on buying personal line insurance firms and to integrate its acquisitions. That year it bought Nikols Sedgwick Group, an Italian insurance firm, and formed RiskAttack (with Zurich US), a risk analysis and financial management concern aimed at technology companies.The cost of integrating its numerous purchases, however, hammered profits in 1999.[14]
Despite its troubles, in 2000 Aon bought Reliance Group's accident and health insurance business, as well as Actuarial Sciences Associates, a compensation and employee benefits consulting company. Later in that year, however, the company decided to cut 6% of its workforce as part of a restructuring effort.[15] In 2003, the company saw revenues increase primarily because of rate hikes in the insurance industry. Also that year, Endurance Specialty, a Bermuda-based underwriting operation that Aon helped to establish in November 2001 along with other investors, went public. The next year Aon sold most of its holdings in Endurance.[16][17]
Aon's New York offices were on the 92nd and 98th–105th floors of the South Tower of the World Trade Center at the time of the September 11 attacks.When the North Tower was struck by American Airlines Flight 11 at 8:46 a.m., an evacuation of Aon's offices was quickly initiated by executive Eric Eisenberg, and 924 of the estimated 1,100 Aon employees present at the time managed to get below the 77th floor before United Airlines Flight 175 crashed between Floors 77 and 85 at 9:03 a.m.[18] Many, however, did not manage to get beneath in the 17 minutes they had between the two impacts. As a result, 176 employees of Aon were killed in the crash or died in the eventual collapse of the tower or from smoke inhalation. At 9:59 a.m., the tower collapsed, killing any survivors still within,[19] including Eisenberg and Kevin Cosgrove.[20]
In 2004–2005, Aon, along with other brokers including Marsh & McLennan and Willis, fell under regulatory investigation under New York Attorney GeneralEliot Spitzer and other state attorneys general. At issue was the practice of insurance companies' payments to brokers (known as contingent commissions). The payments were thought to bring a conflict of interest, swaying broker decisions on behalf of carriers, rather than customers. In the spring of 2005, without acknowledging any wrongdoing, Aon agreed to a $190 million settlement, payable over 30 months.[21]
In the late 2007, Aon divested its two major underwriting subsidiaries: Combined Insurance Company of America (acquired by ACE Limited for $2.4 billion) and Sterling Life Insurance Company (purchased by Munich Re Group for $352 million) sold due to their low margin and capital-intensive nature.[22][23]
In November 2008, Aon acquired reinsurance intermediary and capital advisor Benfield Group Limited for $1.75 billion. The acquisition amplified the firm's broking capabilities, positioning Aon one of the largest players in the reinsurance brokerage industry.[24]
In 2010, Aon acquired Hewitt Associates for $4.9 billion.[25] Aside from drastically boosting Aon's human resources consulting capacity and entering the firm into the business process outsourcing industry, the move added 23,000 colleagues and more than $3 billion in revenue.[26]
In January 2012, Aon announced that its headquarters would be moved to London, although North American operations and jobs remained in Chicago.[27]
In February 2017, Aon sold its employee benefits outsourcing business to private equity firm The Blackstone Group for US$4.8 billion (£3.8 billion).[28]
In February 2020, Aon named Eric Andersen as president of Aon.[29]
In 2021, Aon agreed to merge with Willis Towers Watson; the merger agreement was terminated due to regulatory concerns.[30][31]
Costa Rica
,
Egypt
,
Vietnam
,
Indonesia
, the
United Arab Emirates
,
Myanmar
and
Bangladesh
, between 1983 and 2007, to obtain and retain insurance contracts.
In July 2011, Aon announced that it bought Westfield Financial, the owner of insurance-industry consulting firm Ward Financial Group, from Ohio Farmers Insurance Co.[40]
In October 2012, Aon announced that it agreed to buy OmniPoint, Inc, a Workday consulting firm.Financial terms were not disclosed.[41]
In June 2014, Aon announced that it agreed to buy National Flood Services, Inc., a large processor of flood insurance, from Stoneriver Group, L.P.[42]
In October 2016, Aon's Aon Risk Solutions acquired Stroz Friedberg LLC, a specialised risk management firm focusing on cybersecurity.[43]
In November 2016, Aon acquired CoCubes an online Indian Assessment firm, facilitating hiring of entry-level engineering graduates.[44]
In February 2017, Aon plc agreed to sell its human resources outsourcing platform for US$4.8 billion (£3.8 billion)[28] to Blackstone Group L.P. (BX.N), creating a new company called Alight Solutions.[45]
In September 2017, Aon announced its intent to purchase real estate investment management firm The Townsend Group from Colony NorthStar for $475 million, expanding Aon's property investment management portfolio.[46]
In December 2023, Aon agreed to acquire NFP, a middle-market provider of risk, benefits, wealth and retirement plan advisory services company, for $13.4 billion.[47]
In March 2024, Aon plc acquired the technology assets and intellectual property of Humn.ai, an AI-powered platform. This will enhance its commercial fleet proposition.[48]
Aon Benfield was named 2012 European Reinsurance Broker of the Year, Best European Property Reinsurance Broker and Best European Casualty Reinsurance Broker at the European Intelligent Insurer Awards[56]
Aon Benfield was named Best Global Reinsurance Broking Company for Analytics at Reactions Global Awards 2012[57]
Aon Hewitt was named Top Retirement Consultant of 2012 by PLANSPONSOR Magazine2[54][58]
Aon Hewitt was named Actuarial and Investment Consultant of the Year for 2012 at the Professional Pensions Awards[59]
27.— Note: only first hundred or so words archived, but that is sufficient to support fact here. Nathalie Tadena, Jason Dean, Leslie Scism. Aon Shifts Headquarters to London The Wall Street Journal, 14 January 2013, retrieved 10 May 2013^
